This invention relates to an adaptor that allows a pintle-type trailer coupling designed to be used with an annular eye-type trailer drawbar to be quickly and easily changed into a spherical ball-type trailer coupling.
Trailer couplings that are attached to the bumper or under-carriage of a towing vehicle are generally of two common types; a pintle-type or a spherical ball-type. Trailer drawbars are equipped to mate with one type of coupling or the other. A problem arises when it is desired to have a vehicle equipped with a pintle-type of trailer coupling tow a trailer with a spherical ball-type receptacle.
Prior attempted solutions to the above-mentioned problem have been unacceptable. One solution has been to mount a pintle-type trailer coupling and a spherical-ball type trailer coupling side-by-side on a towing vehicle. Depending upon the design of the vehicle and the method and location that the trailer couplings are designed to be attached to, the attachment of two trailer couplings may or may not be possible or practical. In the very least, mounting two trailer couplings side-by-side requires that at least one of the trailer couplings, or perhaps both, be mounted in a position offset from the centerline of the towing vehicle. This creates an inherently unsafe condition because the trailer and towing vehicle will track differently.
Another solution has been to provide a spherical ball-type coupling that is configured to receive a drawbar eye over the ball. Placing a drawbar eye over a ball rather than a pintle causes loads to be transferred through a small surface area and thus results in rapid wear of both elements.
The subject invention overcomes the foregoing problem by providing a ball carrying adaptor that releasably mounts on a pintle-type trailer coupling. The adaptor includes a crossbar that conformingly mates with the arcuate surface located on the inside of the pintle, resulting in a firm fit between the mated surfaces. The adaptor includes two vertical plates that are spaced apart slightly more than the width of a standard pintle. Aligned mounting holes are located in the vertical plates and a bore is placed in the body of the coupling coaxially with these holes when the adaptor is mounted on the coupling. A pin may then be inserted through the holes and bore to secure the adaptor in place on the coupling. A tongue provided at the end of the plates contains a hole to receive a standard spherical-ball. When the adaptor is installed, the latch of the trailer coupling will still engage the top of the pintle and assure that the adaptor mechanism will not accidentally disengage from the trailer coupling. This system of securing the adaptor to the trailer coupling assures a snug connection even when there are slight variations in the dimensions of the coupling or wear has occurred. In addition one adaptor can be used on several different size trailer couplings.
Accordingly, it is a principal object of the present invention to provide an adaptor for a pintle-type trailer coupling that allows a spherical towing ball to be mounted on the coupling.
It is a further object of the invention to provide such an adaptor in which a crossbar that conformingly mates with the arcuate surface of the pintle and a pin which fits through aligned openings in the adaptor and coupling securely attach the adaptor to the coupling.
It is a further object of the subject invention to provide such an adaptor in which the aligned openings are located in parallel spaced-apart plates that fit over the pintle.
It is a still further object of the invention to provide such an adaptor in which the crossbar has a circular cross-sectioned shape.
The foregoing and other objectives, features and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings